A History of the Atom and its Models一个原子的历史及其模型.doc

A History of the Atomic Model Sarah L. Wood Men need ideas to live, but so do ideas need men to live. The history of science, like all history, is the record, and our judgment of the record, of res gestae: the deeds of fallible men (Greenaway, 1966, pg. 4). This is the history of the atom. It is a tale of success, of failure, of unimaginable good to mankind and inconceivable harm. Like any science, it would be nothing without the men and women who lent their fallible expertise to insure its progression. Unfortunately, the comprehensive biographies of these men and women are the concern of another essay, but their contributions to the atom will be told through five models that represent each major atomic development. Debuting as a solid ball, the atom concept originated in the fifth century before the common era with the Greeks. This model reigned through the early nineteenth century. It was replaced by the plum pudding model in 1897, however, with the discovery of the electron. This too was modified in 1911 with the addition of the recently discovered nucleus and termed the nuclear model. Again the model was soon made obsolete by an improved orbital atom in 1913 in association with the detection of energy levels which accounted for previously unexplained radiated light. Finally, the electron cloud model was proposed in 1930 as a result of wave mechanics and remains the most widely accepted model to this day. These models, though not comprehensive, provide a guideline for addressing the principal advancements in atomic history. The idea of an atom seems so clear if one says the word atom quickly without thought, that one is hardly ever aware of its vagueness (Greenaway, 1966). The atom concept is full of paradox. It is at once the fundamental essence of all that we know, even ourselves and yet the very frustration of the most intelligent men of our day. It is the building block of biology, chemistry, and physics, and yet this bloc